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If you often nap or you're a fan of an afternoon siesta, then you've already adopted a biphasic sleep pattern. Here, we explore the ins and outs of this second-most common sleep cycle.
6 Min Read | By Lewis Ridley
Last Modified 26 June 2025 First Added 8 January 2021
Biphasic sleep is a sleep schedule that breaks your nightly rest into two segments. While many of us are used to sleeping in one uninterrupted block, two-phase sleeping is making a quiet comeback, and it may actually align more naturally with the human body clock.
Let’s explore what biphasic sleep is, how it works and the science behind it, and how you can try it for yourself.
Biphasic sleep is a sleeping pattern that divides sleep into two main periods within a 24-hour cycle. It’s also known as bimodal, segmented, or diphasic sleep.
The sleeping routine includes both a night-time and daytime sleeping interval. This might involve one long sleep and a shorter nap or two moderate-length sleeps spaced apart.
As you can begin to see, this is completely different from the standard monophasic sleeping pattern people commonly adopt, which involves sleeping for 7-8 hours a night. However, as you may have experienced at some point in life, achieving this many hours of sleep can sometimes prove to be a challenge.
There are several common ways biphasic sleep is structured, including:
This type of biphasic sleep is the most common one. In the evening, people sleep for 3-4 hours, wake for 1-2 hours, and then return to sleep. Quiet activities such as reading, meditation, or journaling often fill the waking gap.
With 5-6 hours of sleep at night, and a 60-90 minute nap in the afternoon. Siesta is popular in warmer climates such as Spain and was commonly used to avoid the midday heat, allowing people to recharge before resuming work. But it’s also a common form of biphasic sleep, perfect if you get a midday slump.
Ideal for those with busy daytime hours, or less flexible schedules, it consists of 6 hours of core sleep at night, and a 20-30 minute nap in the afternoon.
Biphasic sleep isn’t just a modern fad; it’s been around for decades and may even be biologically natural.
Historically, the first and second sleeps were widespread in Europe in the Middle Ages. Historian Roger Ekirch analysed over 500 documents, which revealed that people regularly woke for an hour or two at night before returning to sleep.
Ekrich found a study conducted by Thomas Wehr, a sleep scientist from the National Institute of Mental Health. This 1992 study involving 15 men showed that if they were exposed to natural light for several weeks, they naturally adopted a two-phase sleep pattern.
In 2017, a study on the remote community of Mandena in Madagascar showed that those who weren’t in artificial light experienced a period of activity after midnight until 11:30 am, followed by another session of sleep.
This study found that biphasic sleep never vanished, but it dwindled with the introduction of artificial light in the early 19th century. These lights suppressed the production of melatonin, the sleepy hormone. This, in turn, altered people’s circadian rhythms, allowing people to stay up later.
However, people were still waking up at the same time every morning, so their rest was condensed into a single block of sleep. Today, the single-sleep pattern is considered the norm, while science shows that segmented rest may be more natural.
If you’ve heard of biphasic sleep, you’ve probably heard of polyphasic sleep as well.
The key difference between the two is the sleeping intervals. Biphasic sleep involves two separate sleeping segments, whereas polyphasic sleep involves aggressively splitting up sleep into 4-6 different segments throughout the day.
The polyphasic routine splits into three different styles:
You begin to ask yourself the question: Why would anyone do this?
Limiting one’s sleep to just two hours is extreme. However, individuals who follow this extreme sleep schedule claim it makes them more productive and cognitively enhanced.
Here’s what Healthline has to say: ‘People might actively pursue a biphasic or polyphasic sleep lifestyle because they believe it makes them more productive. It creates more time for certain tasks and activities during the day, while retaining the same benefits as monophasic sleep at night.’
Read more with our guide to 4 alternative sleeping cycles.
Biphasic sleep boasts a number of potential benefits, including:
However, many of these pros are derived from studies on napping. They’re not the findings from studies investigating biphasic sleep directly.
However, if we were to look into studies investigating napping and use them as a proxy for biphasic sleep, the results are mixed.
Research in 2010 found that daytime napping has a positive influence on cognitive functioning, with larger benefits seen with naps lasting longer than 30 minutes.
Conversely, one study in 2012 found napping to be a poor method to achieve quality rest and could result in lower cognitive performance. Note that this study was performed on pre-schoolers and may not be generalisable to a broader population.
Biphasic sleep may not work for everyone, whether it’s due to your work, social schedules, or shared household routines. Trying biphasic sleep may also cause sleep disruption as you adjust to it, but you won’t know if you don’t try it.
If you’re curious to try biphasic sleep, here’s how to achieve it:
Use a sleep journal or an app to monitor your energy levels, alertness, and mood throughout the day. Experiment with different sleep times in the evening and nap times in the afternoon, and see how you feel.
Biphasic sleep may not be for everyone, and should be avoided if your lifestyle or work shifts change, or if you suffer from sleep deprivation, chronic fatigue or sleep disorders. Speak to a GP or sleep specialist for more advice.
Biphasic sleep is historically rooted, and it might even offer cognitive and emotional benefits for some. While it won’t suit every lifestyle, those with flexible routines may find it refreshing. Whether you choose long or short naps, or try the first and second sleep approach, listen to your body.
Pair it with our top tips on how to sleep better at night to truly optimise your sleep quality, even if you split it in chunks throughout the day.
See all articles by Lewis Ridley
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